1. Field
One or more aspects of embodiments according to the present invention relate to radio frequency (RF) filters, and more particularly to RF filters that are stacked for improved packaging.
2. Description of Related Art
Printed wiring boards for processing microwave and radio frequency signals (referred to herein collectively as RF signals), e.g., for defense or commercial applications, may include various active and passive RF elements, as well as elements for providing and controlling bias voltages or currents, and for processing intermediate frequency or baseband signals. The RF signal processing elements may include distributed element filters, formed as conductive patterns in a signal layer adjacent to one or two ground layers (and separated from the ground layer or layers by one or two dielectric layers).
The fabrication of a distributed element filters may require tight tolerances, which may increase the cost of fabrication. Further, it may be beneficial to package distributed element filters in a space-efficient manner, to reduce cost and to facilitate the production of a compact system. Thus, there is a need for a cost-effective and compact design for distributed element filters.